Additive for incorporating ultraviolet radiation protection into a polymer

ABSTRACT

An additive for incorporating ultraviolet radiation protection into a synthetic polymer with the additive and the synthetic polymer for forming a synthetic material has a quantity of zinc oxide particles modified with a layer of a reactive group that forms a bond with a synthetic polymer having C—H bonds. A product for incorporating ultraviolet radiation protection into a synthetic polymer prior to forming a synthetic material has a quantity of a synthetic polymer and a quantity of zinc oxide particles modified with a layer of a reactive group that forms a bond with the quantity of the synthetic polymer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/893,985 filed on Feb. 12, 2018, which is now U.S. Pat. No.10,472,523, which was a continuation of U.S. patent application Ser. No.15/064,242 filed on Mar. 8, 2016, which was a continuation-in-part ofU.S. patent application Ser. No. 14/833,317 filed on Aug. 24, 2015,which is now U.S. Pat. No. 9,404,214, which was a continuation of U.S.patent application Ser. No. 14/245,152 filed on Apr. 4, 2014, which isnow U.S. Pat. No. 9,150,824, which was a continuation of U.S. patentapplication Ser. No. 13/632,223 filed on Oct. 1, 2012, which is now U.S.Pat. No. 8,690,964, which was a continuation-in-part of U.S. patentapplication Ser. No. 13/317,152 filed on Oct. 11, 2011, which is nowU.S. Pat. No. 8,277,518.

BACKGROUND

This disclosure relates to an additive for incorporating ultravioletradiation (UV) protection into a polymer, and more specifically, to anadditive for incorporating UV protection into a synthetic polymer withthe additive and the synthetic polymer for use in manufacturing asynthetic fabric, yarn, textile or garment.

Ecological friendly fabrics or Eco-friendly fabrics are gaining inpopularity and use in clothing. An Eco-friendly fabric may be a naturalfiber such as cotton, hemp, or bamboo which has been grown in soil thathas not been treated with pesticides for a number of years. Someexamples of other Eco-friendly fabrics are organic cotton, sisal, acombination of hemp and recycled rayon, a combination of hemp andcotton, broadcloth, denim, linen, and a combination of bamboo andrecycled rayon. Natural fibers, which may be derived from plants oranimals, such as wool, angora, silk, alpaca, cashmere, and silk are alsoexamples of Eco-friendly fabrics. Synthetic fabrics, which may be madefrom synthetic sustainable products, such as nylon, rayon, olefin,spandex, and tencel are also examples of Eco-friendly fabrics.

To assist an individual in determining whether a garment has protectionagainst ultraviolet radiation, a rating system has been developed. Thisrating system is known in the industry as the UPF (UltravioletProtection Factor) rating system. Clothing having a rating of UPF 50 areable to block out 98% of the sun's ultraviolet radiation. Further, byway of example, a garment having a rating of UPF 15-24 will only blockout 93.3% to 95.9% of ultraviolet radiation. Exposure to the sun'sharmful ultraviolet radiation (known as UVA/UVB rays) can damage theskin, can cause sunburn, and can lead to skin cancer over prolongedexposure.

There are a number of factors that affect the level of ultravioletradiation protection provided by a fabric and the UPF rating. Somefactors are the weave of the fabric, the color of the fabric, the weightof the fabric, the fiber composition of the fabric, the stretch of thefabric, moisture content of the fabric. If the fabric has a tight weaveor a high thread count then the fabric will have a higher UPF rating.However, even though the fabric has a higher UPF rating, the fabric maybe less comfortable because a tighter weave or higher thread count meansthat the fabric is heavy or uncomfortable to wear. Another factor thataffects protection is the addition of chemicals such as UV absorbers orUV diffusers during the manufacturing process. As can be appreciated,some of the features that make a garment comfortable to wear also makethe garment less protective. A challenge for a clothing manufacturer isto provide clothing having both protection from the sun and beingcomfortable to wear.

Athletic clothing or active wear clothing is typically manufactured fromsynthetic material such as polyester or nylon. Polyester may be formedinto a filament yarn that is used to weave a fabric or garment. To formpolyester, dimethyl terephthalate is placed in a container and firstreacted with ethylene glycol in the presence of a catalyst at atemperature of 302-410° F. The resulting chemical, a monomer alcohol, iscombined with terephthalic acid and raised to a temperature of 472° F.Newly-formed polyester, which is clear and molten, is extruded through aslot provided in the container to form long ribbons. the long moltenribbons are allowed to cool until they become brittle. The ribbons arecooled and then cut into tiny polymer chips. These tiny polymer chipsare then melted at 500-518° F. to form a syrup-like melt or liquid. Thismelt is put into a metal container called a spinneret and forced throughits tiny holes to produce special fibers. The emerging fibers arebrought together to form a single strand. This strand is wound on abobbin for further processing or to be woven into yarn.

Therefore, it would be desirable to provide an additive forincorporating ultraviolet radiation protection into a polymer prior to apolymer yarn being fabricated. Moreover, there is a need for a processfor incorporating UV protection into a polymer so that the polymer maybe further processed into a yarn that may be used to manufacture afabric so that the fabric may be used to protect an individual from UVradiation. Furthermore, it would be advantageous to incorporate adequateprotection in a garment, fabric, or textile to protect against exposureto UV radiation, to increase the UV resistance of a garment, fabric, ortextile, or to enhance UV radiation absorption of a garment, fabric, ortextile to protect an individual from UV radiation.

BRIEF SUMMARY

In one form of the present disclosure, an additive for incorporatingultraviolet radiation protection into a synthetic polymer with theadditive and the synthetic polymer for forming a synthetic material isdisclosed which comprises a quantity of zinc oxide particles modifiedwith a layer of a reactive group that forms a bond with a syntheticpolymer having C—H bonds.

In another form of the present disclosure, an additive for incorporatingultraviolet radiation protection into a synthetic polymer with theadditive and the synthetic polymer for forming a synthetic material isdisclosed which comprises a quantity of zinc oxide particles and aquantity of a phosphoether of 4-hydroxybenzophenone.

In yet another form of the present disclosure, a method for preparing anadditive for incorporating ultraviolet radiation protection into asynthetic polymer with the additive and the synthetic polymer forforming a synthetic material comprises the steps of suspending aquantity of zinc oxide particles in a solution of 98% ethyl alcohol,suspending a quantity of benzophenone silane linker in the solution ofzinc oxide particles and 98% ethyl alcohol, adjusting the pH of thesolution of zinc oxide particles, 98% ethyl alcohol, and benzophenonesilane linker to 12, placing the pH adjusted solution of zinc oxideparticles, 98% ethyl alcohol, and benzophenone silane linker into acentrifuge, recovering the zinc oxide particles prepared bycentrifugation after a period of time, and drying the recovered preparedzinc oxide particles.

The present disclosure provides an additive for incorporatingultraviolet radiation protection into a polymer to be used to produce ormanufacture a fabric which is lightweight and can be worn in anytemperature.

The present disclosure provides an additive for incorporatingultraviolet radiation protection into a polymer for providing enhancedprotection from both UVA and UVB radiation.

The present disclosure also provides an additive for incorporatingultraviolet radiation protection into a polymer which retainsultraviolet radiation protection after use or after cleaning.

The present disclosure provides an additive for incorporatingultraviolet radiation protection into a polymer to be used to produce ormanufacture a fabric which is comfortable to wear.

The present disclosure provides an additive for incorporatingultraviolet radiation protection into a polymer which also hasantimicrobial protection incorporated therein.

The present disclosure also provides an additive for incorporatingultraviolet radiation protection into a polymer which can bemanufactured without increasing the cost of the polymer.

The present disclosure provides an additive for incorporatingultraviolet radiation protection into a polyester that is incorporatedinto active wear clothing or athletic clothing.

The present disclosure is directed to an additive for incorporatingultraviolet radiation protection into a polymer, such as a syntheticpolymer, that is used to produce a synthetic yarn that is employed tomanufacture a fabric or garment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Various methods or processes are disclosed herein for the immobilizationof UV-blocking nanoparticles on Eco-friendly fabric to incorporate UVprotection in the fabric. Once the UV-blocking nanoparticles areattached, the Eco-friendly fabric will be able to protect a wearer ofthe fabric from UV radiation. One method comprises direct immobilizationfrom in situ formation of the particles. A second method comprisescarboxylation or phosphorylation of the fabric followed by binding ofthe UV-blocking nanoparticles to the modified fabric. A third methodcomprises modifying UV-blocking nanoparticles with a self-assembledmonolayer (SAM) or polymer layer containing an active chemical groupcapable of binding to the fabric and deposited on the fabric fromsolution.

ZnO (zinc oxide) nanoparticles are generally formed by the precipitationof a zinc salt (acetate, sulfate, nitrate, chloride) using eitheraqueous hydroxide or an amine. The following examples disclose directimmobilization from in situ formation of the ZnO nanoparticles.

Example 1 Solution Sol-Gel Process, Hydroxide Base

4.39 g. zinc acetate (20 mmol) is dissolved in 100 mL deionized ordistilled water. A textile is added to this solution and 100 mL 0.4MNaOH is added while mixing. The suspension is mixed for 2 hours to forma suspension of zinc oxide nanoparticles in contact with the fabric. Thetextile is removed from the nanoparticle suspension and laundered in ahousehold washing machine. As can be appreciated, a fabric may betreated to have ultraviolet radiation protection incorporated in thefabric by the steps of dissolving zinc acetate or other zinc salt in aliquid to form a solution containing Zn(II) ions, adding a fabric to thesolution, mixing the solution and the fabric, and adding a base to thesolution when the solution and the fabric are being mixed to form asuspension of zinc oxide nanoparticles in contact with the fabric.

Example 2 Solution Sol-Gel Process, Amine Base

4.39 g. zinc acetate (20 mmol) is dissolved in 100 mL deionized water. Atextile is added to this solution while mixing and 40 mmol amine isadded while mixing. Amines used may include ethanolamine,ethylenediamine, (tris)hydroxymethylaminomethane, or others. The textileis removed from the nanoparticle suspension and laundered in a householdwashing machine.

Example 3 Mechanochemical Process

5.75 g. zinc sulfate heptahydrate (20 mmol) and 0.88 g (15 mmol) sodiumchloride are powered finely and blended, then placed with a textile in aball mill or similar mechanical mixer. 1.6 g (40 mmol) sodium hydroxideis powdered and added to the mixer. After twenty minutes, the textile isremoved and rinsed thoroughly with water.

The following examples disclose carboxylation or phosphorylation of thefabric followed by binding of the UV-blocking nanoparticles to themodified fabric.

Example 4 Modification of Textile with Phosphonic Acid Groups

For this process it will be necessary to modify a textile withphosphonic acid groups. This can be accomplished in a number of ways,but it is desirable to use materials that are non-toxic and/or renewablysourced chemicals. Phosphorylated cellulose should form covalentlinkages with ZnO and TiO₂ nanoparticles. The interaction betweenphosphonates and oxide surfaces are used for modification of the oxidesurfaces. In essence, the procedure consists of condensing the cellulosetextile with a bis(phosphonic acid), phosphonate, or phosphate species,either organic or inorganic. Urea may be added to forestalldiscoloration of the textile. Phosphorylation takes place driven by theelimination of water. The resulting phosphorylated textile will directlybind both zinc oxide and titanium oxide nanoparticles. It will benecessary to restrict the degree of phosphorylation of the textile toprevent great alteration in the properties of the textile by controllinga reaction time. This process does not require in situ synthesis of thezinc oxide nanoparticles. Commercially available zinc oxidenanoparticles may be used.

A sample of cotton textile is wetted with a 10% v/v solution ofphosphoric acid or bis-phosphonic acid containing 10-30% w/v urea. Thetextile is pressed to remove excess solution and baked in an oven at85-100° C. for 5 minutes to dry, then at 170° C. for 2-4 minutes to cureunreacted groups. The textile is removed from the oven and washed withwater. The textile is then used without further modification insubsequent deposition steps.

Example 5 Modification of a Textile by Partial TEMPO-H₂O₂ Oxidation

A sample of cotton textile (ca. 1 g) is added to a solution composed of90 mL water with 10 mg (0.065 mmol) TEMPO and 0.22 g (2 mmol) sodiumbromide. Hydrogen peroxide 3% is added (0.9 mL, 1 mmol) and the reactionstirred at RT for 10 minutes to 2 hours. The material is washed withwater, dried, and used without further modification in the following ZnOdeposition step.

Example 6 Immobilization of Nanoparticles on a Phosphorylated orCarboxylated Cellulose Surface

Ca. 1 mg/mL nanoparticles are suspended in water, ethyl alcohol, orother solvent. The phosphorylated or carboxylated cellulose textile isadded to the suspension and the suspension is gently mixed over areaction period of 1 to 12 hours. The textile is removed from thesuspension and subjected to tumble drying or another drying procedure toforce surface condensation and cure remaining groups.

The following example discloses modifying UV-blocking nanoparticles witha self-assembled monolayer (SAM) or polymer layer containing an activechemical group capable of binding to the fabric and deposited on thefabric from solution.

Example 7 Grafting to Attachment of Cellulose to Nanoparticles ThroughReactive Groups

In this method, ZnO particles are synthesized separately by any of themeans discussed in Examples 1-3 or the ZnO particles may be purchasedcommercially. The ZnO particles are suspended in water or a weaknon-nucleophilic aqueous buffer and an organosilane or phosphonate withone of the given combinations of reactive groups, as shown in Table 1,is added. Multidentate ligand or polymeric silanes may also be added tothis mixture to facilitate the formation of a durable reactive layer andan oxide, alkoxide, or salt of another metal such as Ti or Si may beadded first to form a surface layer of another oxide in the ZnOparticles. After a reaction time of 1 to 12 hours, the particles arecollected by centrifugation and washed with water. The particles arethen resuspended in water or buffer and added to the textile. Theconditions for binding of the particles to the textile vary depending onthe headgroup, as shown in Table 1, but may involve direct applicationof the particles to the textile similarly to the process disclosed inExample 6, raising the pH of the suspension containing the textile, orheating the textile either in or after removal from the suspension. Thisprocess has the advantage of yielding extremely fine control over thenature of the linkage between particle and textile. This process has afurther advantage in that the treated textile will be durable due to therobustness of self-assembled siloxane layers on oxide.

TABLE 1 Molecule name Commer- (if commercially cially available) LinkerHeadgroup available? 3-glycidoxypropyl- Triethoxysilane Glycidyl etherYes triethoxysilane 2-(3,4-cyclohexyloxy) Triethoxysilane Cyclohexyloxide Yes ethyltriethoxysilane Hydroxymethyl- TriethoxysilaneHydroxymethyl Yes triethoxysilane Isocyanatopropyl TrimethoxysilaneIsocyanate Yes trimethoxysilane Bis(triethoxysilyl) Triethoxysilane N/AYes ethane (2) 6-azidosulfonylhexyl Triethoxysilane Axidosulfonyl Yestriethoxysilane Triethoxysilane Vinylsulfone No Triethoxysilane Arylazide No Phosphonate Glycidyl ether No Phosphonate Cyclohexyl oxide NoPhosphonate Azidosulfonyl No Phosphonate Vinyl sulfone No PhosphonateAryl azide No Bis(triethoxysilyl) Triethoxysilane Secondary amine Yespropylamine (2) APTES/EGDE Triethoxysilane Amine/Ethylene Yes, 2 glycoldiglycidyl components ether

The terms “fabric” or “textile” are intended to include fibers,filaments, yarn, melt, textiles, material, woven and non-woven fabric,knits, and finished products such as garments. The methods describedherein may be used in treating fibers, filaments, yarn, textiles, andfabrics. For example, fibers may be initially treated by use of one ormore of the disclosed methods and the fibers may be manufactured into afabric or a textile. Once manufactured into a fabric, the fabric may betreated by use of one or more of the disclosed methods. In this manner,individual fibers and the entire fabric are treated to incorporate UVprotection. As can be appreciated, the treated fabric may be used tomanufacture a garment such as, by way of example only, shirts, pants,hats, coats, jackets, shoes, socks, uniforms, athletic clothing, andswimwear. It is also possible and contemplated that the treated fabricmay be used to construct non-apparel items such as blankets, sheets,sleeping bags, backpacks, and tents.

Further, it is also possible to further modify ZnO particles with a thinlayer of other oxides in a “core-shell” type procedure by adding areactive precursor to a suspension of the ZnO oxides. Oxides that can bedeposited in this manner include SiO₂ from tetraethoxysilane (TEOS) orsodium silicate, and Al₂O₃ and TiO₂ either from the appropriatealkoxides, aluminate/titanate compounds, or other hydrolyzable aluminumor titanium compounds. A second oxide shell of this type may enhance theformation and stability of both directly applied ZnO-textile conjugatesand those formed by modification of nanoparticles with an organicmonolayer. ZnO can also be modified by the addition of a multidentatesilane along with a silane containing the desired functional group. Themultidentate silane yields a more densely crosslinked siloxane surfacethan monodentate silanes alone, forming a more stable layer on ZnO.

Although the above examples and methods are applicable to themanufacturing process in which ultraviolet radiation protection isincorporated into the fabric, textile, or garment when initiallyproduced, the following discloses various methods of incorporatingultraviolet radiation protection directly to clothing being laundered.By use of the following methods, a garment after purchase may be made aprotected garment by an end user.

In general, the methods may comprise the self-assembly of certainpolyanionic materials onto a ZnO surface to create a linker which willbind the particles to a cellulose (cotton) surface. Several acidic oroxyanion functional groups are capable of self-assembly onto ZnO. Thesefunctional groups include siloxane, silanol, carboxylic acid,carboxylate, phosphonic acid, phosphonate, boronic acid or other groupscapable of binding to oxide layers. Boronic acid is capable of formingvery strong interactions with carbohydrates, including theglycosidically linked glucose units making up cellulose. One method orapproach is to prepare a polymer bearing boronic acid groups and usethat polymer to bind ZnO to cotton.

Various methods or processes are disclosed herein for the treatment offabric to incorporate UV protection in the fabric by use of a laundryadditive. One method is identified as the cellulose-to-oxide method. Asecond method is termed the oxide-to-cellulose method. A third method isdescribed as the free mixing method.

Example 8 the Cellulose-to-Oxide Method

In this method, cotton garments are pre-treated with boronic acidpolymer resulting in cloth or fabric coated with boronic acid groupscapable of binding to suspended uncoated ZnO particles. A home washingmachine having the capability of adding a substance on a delayed basismay be used. In particular, boronic acid polymer is added to laundrydetergent or added at the beginning of the laundry cycle. A suspensionof ZnO particles may be added to a compartment in the washing machinethat will dispense the particles on a delayed basis. For example,several washing machines have a compartment for storing bleach which isdispensed later on in the laundry cycle. The suspension of ZnO particlesmay be placed in the bleach compartment to be dispensed at the time thatbleach would normally be dispensed into the washing machine. The washingmachine would initially mix the clothing with the boronic acid material.This will result in the clothing bearing boronate groups. At the end ofthe delayed period the washing machine will dispense the suspension ofZnO particles into the washing machine. The ZnO particles will bind tothe boronate groups and become attached to the clothing. It is alsopossible and contemplated that the suspension of ZnO particles may bemanually added to the washing machine in a delayed manner. Manuallyadding the suspension may be required if the washing machine is notequipped with a compartment for adding bleach on a delayed basis.

Example 9 Oxide-to-Cellulose Method

In this method, ZnO particles are treated with boronic acid polymer.Once prepared, these particles may be either mixed with laundrydetergent and distributed in that form or sold as a separate additivethat may be added to laundry detergent. The particles mixed with thelaundry detergent or the separate additive is used in the washingmachine as normal. During the course of the wash cycle, the boronic acidgroups attach to the ZnO particles would assemble on and bind to cottonor other cellulose clothing. This results in an ultraviolet protectedgarment.

Example 10 Free Mixing Method

In this method, boronic acid polymer and ZnO particles (untreated) areincorporated into the laundry detergent preparation in the solid phase.When added to a laundry cycle or wash cycle the detergent and water willsolubilize these materials causing boronic acid polymer to assemble onboth ZnO and cellulose. This will result in linked ZnO material. Thismethod may require more boronic acid polymer and ZnO particles then themore controlled methods disclosed in Examples 8 and 9 to yield adequategrafting densities of ZnO on clothing.

Use of any of the methods disclosed in Examples 8, 9, or 10 will resultin ZnO particles being bound to the fabric that is being washed in aconventional household washing machine. Once the ZnO particles are boundto the fabric, the fabric will have incorporated therein ultravioletradiation protection. It is also possible and contemplated that thevarious methods described in Examples 8, 9, and 10 may be used more thanonce to incorporate ultraviolet radiation protection into clothing. Forexample, clothing may be treated by use of one or more of these methodsand over time and after numerous washings the ultraviolet radiationprotection may diminish. If there is any concern about the ultravioletradiation protection of the garment, the garment may be washed using thevarious methods discussed in Examples 8, 9, and 10. Further, it ispossible that a consumer may purchase a garment that has been treatedusing the methods described in Examples 1-7. Again, over time theultraviolet radiation protection of the garment may decline. Theconsumer may use the methods disclosed in Example 8, 9, and 10 to washthe garment to again incorporate ultraviolet radiation protection intothe garment.

All synthetic material such as polyester and nylon that is used in themanufacture of athletic clothing or active wear clothing may be renderedUV-absorbing using a ZnO preparation. These types of fabrics may resisttreatment using the methods as outlined with respect to Examples 8, 9,and 10. One solution to this problem is to prepare ZnO particles coatedwith functional groups capable of being grafted directly to polyester ornylon materials. This may be accomplished by using benzophenonephotografting chemistry. The following examples and methods areapplicable to the manufacturing process in which ultraviolet radiationprotection is incorporated into the artificial or synthetic composition,polymer, fabric, textile, or garment when initially produced.

The following methods provide for the direct grafting of ZnO particlesto nonpolar, non-natural polymers such as nylon and polyester. Nylon andpolyester have little in the way of chemical functionality, containingonly aliphatic and aromatic C—H bonds and amide or ester linkagesbetween monomers. The method is capable of directly functionalizing C—Hbonds. The following method describes preparing ZnO particles coatedwith functional groups capable of being grafted directly to polyester ornylon materials by using the photografting reaction of benzophenone.

Example 11 Grafting ZnO onto Artificial or Synthetic Fibers

In this method, an artificial fabric composed of polyester, nylon, orother polymer lacking hydroxyl functional group is modified by use of apreparation of a zinc oxide particle modified with a layer of reactivegroups capable of C—H activation. Examples of the reactive functionalgroup capable of C—H activation are benzophenone, sulfonylazides, arylazides, or diazonium salts. The prepared particles are coated onto thefabric and a reaction is initiated using UV light, heat, or both. By wayof example only, a mercury-vapor UV lamp may be used and the time forexposure may be one hour. Unbound particles are washed off the fabric.This second step, a curing step, bonds the prepared particles to thefabric. This method adds a second UV-absorbing chromophore whichcross-links and becomes further bonded to the polymer surface of thefabric upon exposure to UV light. In this method, zinc oxide particlescan be composed of pure zinc oxide or zinc oxide coated with aluminum,titanium, or silicon oxides in a core-shell configuration. The result isan artificial fabric with photografted zinc oxide particles.

By way of example, the zinc oxide particles were prepared in thefollowing manner. Five grams of zinc oxide nanoparticles were used andsuspended in a solution of 98% ethyl alcohol. Two grams of benzophenonesilane linker were suspended in this solution and the pH of the solutionwas adjusted to 12. After twelve hours, the zinc oxide particles wererecovered by centrifugation and dried overnight at 50-60° C. in an oven.

It is also possible to prepare a phosphoether of 4-hydroxybenzophenoneand use this self-assembling molecule to functionalize ZnO particles.The resulting particles, having a monolayer of nonpolar molecules, willbe substantially nonpolar and will adhere to nonpolar polyester andnylon. In order to bond the particles to the polymer surface an UV lightmay be used to initiate a reaction. Again, the process has the advantageof adding a second UV absorbing chromophore which cross-links andbecomes further bonded to the polymer surface upon exposure to UV light.

The following describes an additive for incorporating UV protection intoa polymer prior to the polymer being placed into a spinneret or prior tothe polymer being formed into fibers. Nylon and polyester have little inthe way of chemical functionality, containing only aliphatic andaromatic C—H bonds and amide or ester linkages between monomers. Theadditive is capable of directly functionalizing C—H bonds.

Example 12 Additive

An artificial fabric composed of polyester, nylon, or other polymerlacking hydroxyl functional group is modified by use of an additive of aquantity of zinc oxide particles modified with a layer of a reactivegroup that forms a bond with a synthetic polymer having C—H bonds.Examples of the reactive functional group capable of C—H activation arebenzophenone, sulfonylazides, aryl azides, diazonium salts, isocyanate,oxime, and azo. The prepared particles may be added to the syntheticpolymer prior to the synthetic polymer being placed into a spinneret.Further, it is also contemplated that the additive may be packaged withthe synthetic polymer and the packaged additive and synthetic polymermay be placed into the spinneret. The modified zinc oxide particles canalso be coated with aluminum, titanium, or silicon oxides in acore-shell configuration.

By way of example, the zinc oxide particles were prepared in thefollowing manner. A quantity of zinc oxide particles was suspended in asolution of 98% ethyl alcohol, a quantity of benzophenone silane linkerwas suspended in the solution of zinc oxide particles and 98% ethylalcohol, adjusting the pH of the solution of zinc oxide particles, 98%ethyl alcohol, and benzophenone silane linker was adjusted to a pH of12, the pH adjusted solution of zinc oxide particles, 98% ethyl alcohol,and benzophenone silane linker was placed into a centrifuge, the zincoxide particles prepared by centrifugation was recovered after a periodof time, and the recovered prepared zinc oxide particles were dried. Byfurther way of example only, five grams of zinc oxide nanoparticles wereused and suspended in a solution of 98% ethyl alcohol. Two grams ofbenzophenone silane linker were suspended in this solution and the pH ofthe solution was adjusted to 12. After twelve hours, the zinc oxideparticles were recovered by centrifugation and dried overnight or foreight hours at 50-60° C. in an oven.

By way of example only and in not a limiting sense, it is also possibleto prepare a phosphoether of 4-hydroxybenzophenone and use thisself-assembling molecule to functionalize ZnO particles. The resultingparticles, having a monolayer of nonpolar molecules, will besubstantially nonpolar and will adhere to nonpolar polyester or nylon.The resulting or modified zinc oxide particles can also be coated withaluminum, titanium, or silicon oxides in a core-shell configuration.Further, it is to be understood that many other benzophenone derivativesare suitable for use to prepare a self-assembling molecule tofunctionalize ZnO particles.

From all that has been said, it will be clear that there has thus beenshown and described herein an additive for incorporating ultravioletradiation protection into a polymer which fulfills the variousadvantages sought therefore. It will become apparent to those skilled inthe art, however, that many changes, modifications, variations, andother uses and applications of the subject additive for incorporatingultraviolet radiation protection into a polymer are possible andcontemplated. All changes, modifications, variations, and other uses andapplications which do not depart from the spirit and scope of thedisclosure are deemed to be covered by the disclosure, which is limitedonly by the claims which follow.

What is claimed is:
 1. A method for preparing an additive forincorporating ultraviolet radiation protection into a synthetic polymerwherein the method comprises the steps of: suspending a quantity of atleast five grams of zinc oxide particles in a solution of 98% ethylalcohol; suspending a quantity of benzophenone silane linker in thesolution of zinc oxide particles and 98% ethyl alcohol; adjusting the pHof the solution of zinc oxide particles, 98% ethyl alcohol, andbenzophenone silane linker; placing the pH adjusted solution of zincoxide particles, 98% ethyl alcohol, and benzophenone silane linker intoa centrifuge; recovering the zinc oxide particles prepared bycentrifugation after a period of time; and drying the recovered preparedzinc oxide particles for a period of time.
 2. The method of claim 1wherein the quantity of benzophenone silane linker is two grams.
 3. Themethod of claim 1 wherein the period time that the zinc oxide particlesprepared by centrifugation are recovered is twelve hours.
 4. The methodof claim 1 wherein the time that the recovered prepared zinc oxideparticles are dried is eight hours.
 5. The method of claim 1 wherein therecovered prepared zinc oxide particles are dried in an oven.
 6. Themethod of claim 1 wherein the recovered prepared zinc oxide particlesare dried in an oven set at 50-60° C.
 7. The method of claim 1 whereinthe pH of the solution of zinc oxide particles, 98% ethyl alcohol, andbenzophenone silane linker is adjusted to a pH of
 12. 8. A method forpreparing an additive for incorporating ultraviolet radiation protectioninto a synthetic polymer wherein the method comprises the steps of:suspending a quantity of at least five grams of zinc oxide particles ina solution of 98% ethyl alcohol; suspending a quantity of a reactivegroup capable of C—H activation in the solution of zinc oxide particlesand 98% ethyl alcohol; adjusting the pH of the solution of zinc oxideparticles, 98% ethyl alcohol, and reactive group capable of C—Hactivation; placing the pH adjusted solution of zinc oxide particles,98% ethyl alcohol, and reactive group capable of C—H activation into acentrifuge; recovering the zinc oxide particles prepared bycentrifugation after a period of time; and drying the recovered preparedzinc oxide particles for a period of time.
 9. The method of claim 8wherein the quantity of reactive group capable of C—H activation is twograms.
 10. The method of claim 8 wherein the period time that the zincoxide particles prepared by centrifugation are recovered is twelvehours.
 11. The method of claim 8 wherein the time that the recoveredprepared zinc oxide particles are dried is eight hours.
 12. The methodof claim 8 wherein the recovered prepared zinc oxide particles are driedin an oven.
 13. The method of claim 8 wherein the reactive group capableof C—H activation is benzophenone.
 14. The method of claim 8 wherein thereactive group capable of C—H activation is sulfonylazides.